DE69933015T2 - SUSPENSION FOR THE CHEMICAL-MECHANICAL POLISHING OF COPPER SUBSTRATES - Google Patents

Description

BACKGROUND THE INVENTION

(1 Scope the invention

These The invention relates to a chemical mechanical polishing slurry, the a complexing agent, at least one oxidizing agent and at least having an abrasive. The mud is remarkable in that that he has no film-forming agent. The quantities and types of Oxidizing agents and complexing agents are selected so that they maximize polishing while minimizes the depth of any passivation layer on the substrate surface becomes. The chemical-mechanical polishing slurry is for polishing metal layers associated with semiconductor fabrication and thin films usable. More specifically This invention relates to chemical mechanical polishing slurry three components, especially for polishing multiple metal layers and thin films formulated with one of the layers or one of the films Copper or a copper-containing alloy.

(2) Description of the state of the technique

Integrated circuits consist of millions of active devices formed in or on a silicon substrate. The active devices, which are initially isolated from each other, are connected together to form functional circuits and components. The devices are interconnected by the use of well-known multi-level wirings. Wiring structures typically include a first metallization layer, a wiring layer, a second metallization level, and sometimes a third and subsequent metallization level. Dielectric intermediate planes, such as doped and undoped silicon dioxide (SiO ₂ ), are used to electrically insulate the various metallization levels in a silicon substrate or source. The electrical connections between different wiring levels are made through the use of metallized vias. U.S. Patent No. 4,789,648, which is incorporated herein by reference, discloses a method for making multiple metallization layers and metallized vias in insulator films. Similarly, metal contacts are used to form electrical connections between wiring levels and devices formed in a source. The metal vias and contacts may be filled with various metals and alloys including titanium (Ti), titanium nitride (TiN), tantalum (Ta), aluminum copper (Al-Cu), aluminum silicon (Al-Si), copper (Cu), tungsten (W) and combinations thereof. In the metal vias and contacts, an adhesion layer such as titanium nitride (TiN) and / or titanium (Ti) is generally used to cause the through metals to adhere to the SiO ₂ substrate. At the contact level, the barrier film functions as a diffusion barrier to avoid reacting the filler metal with SiO ₂ .

at In a semiconductor manufacturing process, metal passages and / or contacts through a thin metal deposit formed, followed by a chemical-mechanical (CMP) polishing step followed. In a typical process, through holes are through an intermediate level dielectric / interlevel dielectric (ILD) too Etched intermediate lines or to a semiconductor substrate. After that is generally over the intermediate level nonconductor a thin adhesion layer such as formed of titanium nitride and / or titanium and in the etched through hole directed. Then, a metal film is formed over the adhesion layer and into the through hole deposited in a thin area. The deposition is continued until the through hole with the thin surface deposited Metal filled is. After all it will be overcast metal removed by chemical mechanical polishing (CMP) to form metal passages. method for the production and / or for chemical mechanical polishing (CMP) of intermediate level dielectrics in U.S. Patent Nos. 4,671,851, 4,910,155 and 4,944,836.

In a typical chemical mechanical polishing process, the substrate is positioned in direct contact with a rotating polishing pad. A carrier applies pressure to the backside of the substrate. During polishing, the pad and table are rotated while maintaining a downward force against the back surface of the substrate. A grinding and chemically reacting solution, commonly referred to as "sludge", is deposited on the pad during polishing, and the mud initiates the polishing process by chemically reacting with the film being polished The polishing process is accomplished by the rotational motion of the pad relative to the substrate, when sludge is applied to the interface between die and pad, polishing is continued until the desired film on the insulator has been removed The sludge composition is a significant factor in the chemical mechanical polishing step of the election For example, with the oxidizer, abrasive, and other useful additives, the polishing slurry can be engineered to provide effective polishing of metal layers with desired polishing rates while minimizing surface imperfections, defects, corrosion, and erosion. In addition, the polishing slurry can be used to provide controlled polishing selectivities to other thin film materials used in current integrated circuit technology, such as titanium, titanium nitride and the like.

typical chemical-mechanical polishing slurry contain a grinding material, for example silica or alumina, which in an oxidizing aqueous Float medium. In U.S. Patent No. 5,244,534 to Yu et al. For example, an alumina, hydrogen peroxide, and either Mentions sludge containing potassium or ammonium hydroxide, the usable for the removal of tungsten with predictable rates, with little removed from the underlying insulating layer becomes. In U.S. Patent No. 5,209,816 to Yu et al. is a mud discloses perchloric acid, Hydrogen peroxide and a solid abrasive material in an aqueous Contains medium. Cadien and Feller U.S. Patent No. 5,340,370 discloses a tungsten polishing slurry discloses about 0.1M red blood lye salt, about 5% by weight Silica and potassium acetate contains. acetic acid is added to buffer the pH to about 3.5.

In U.S. Patent No. 4,789,648 to Beyer et al. is a mud formulation using alumina abrasives in conjunction with Sulfuric, nitric and acetic acids and deionized water. In U.S. Pat. 5,391,258 and 5,476,606 are sludges for polishing a Discloses metal and silica of existing composite material, the one watery Medium, abrasive particles and an anion comprising the rate the gravel erosion controls. Other polishing slurry for use in chemical-mechanical polishing applications are described in U.S. Patent No. 5,527,423 to Neville et al., U.S. Patent 5,354,490 to Yu et al., U.S. Patent No. 5,157,876 to Medellin, U.S. Patent No. 5,137,544 by Medellin and U.S. Patent No. 4,956,313 to Cote et al.

At the The prior art discloses various mechanisms by the metal surfaces with whitewash can be polished. The metal surface can be polished using a slurry in which no Cover layer is formed, in which case the process with the mechanical removal of metal particles and their dissolution in the mud is continued. In such a mechanism should the chemical dissolution rate be low to wet etching to avoid. However, a more preferred mechanism is one in a thin one abradable layer uninterrupted by the reaction between the metal surface and one or more components in the slurry, such as a complexing agent and / or a film-forming layer is formed becomes. The thin one abradable layer is then controlled by mechanical action ablated. Once the mechanical process is stopped, remains a thin passive Film on the surface and controls the wet etching process. The control of the chemical-mechanical polishing process is a lot easier when polishing with a chemical-mechanical polishing slurry is performed using this mechanism.

Efforts to Development of copper sludges for chemical mechanical polishing are disclosed in the literature. The RPI experiment (J.M. Steigerwald et al, Electrochemical Potential Measurements during the Chemical-Mechanical Polishing of Copper Thin Films / Electrochemical potential measurements during the chemical-mechanical Polishing copper thin films, Mat. Res. Soc. Symp. 337, 133, (1994)) focuses on the Use of ammonium compounds (ammonium nitrate, chloride, hydroxide), nitric acid and aluminum abrasives. It is believed that the copper dissolution of 2 nm / min. (after electrochemical measurement) of a film-free area he follows. However, it is reported that the polishing rates over 400 nm / min. lie. The discrepancy is explained by the mechanical Exposure to the formation of Cu deposits meaning is measured, which are then resolved by a solution. They are not selectivity factors given.

In Q. Luo et al. Chemical-Mechanical Polishing of Copper in Acidic Media Proceedings / Chemomechanical Polishing of Copper in Acid Media, Procedures - First International Chemical-Mechanical Polish (CMP) for VLSI / LSI Multilevel Interconnection Conference (CMP-MIC) / First International Conference for chemical-mechanical Polishing or VLSI / LSI multi-level wiring (CMP-MIC), Santa Barbara, 22.-23. February (1996), is the use of a chemical mechanical polishing slurry revealing a very aggressive etchant, Fe nitrate, pH 1-2 in combination with an inhibitor (benzotriazole), a sludge stabilizing agent surfactant Substance (polyethylene glycol) and alumina. The chemical Reaction becomes evident by a formation of a corrosion inhibiting Filmes, namely Controlled Cu-benzotriazole, the surfactant Substance undermines its protective effect. The selectivity to oxide is with 15: 1 to 45: 1 indicated.

The Electrochemical work relating to chemical-mechanical polishing at Sematech Laboratories is in R. Carpio et al., Initial Study On Copper CMP Slurry Chemistries, Thin Solid Films / Initial Chemistry-Mechanical Study Copper Polishing Slurry Chemistry, Solid Thin Films, 262 (1995). In the reference, the application of electrochemistry in the basic Characterization of plausible sludge investigated. In addition to Several others use potassium permanganate as the sludge oxidizer used.

In H. Hirabayashi et al., Chemical-Mechanical Polishing of Copper using a Slurry Composed of Glycine and Hydrogen Peroxides, Proceedings / Chemo-Mechanical Polishing copper using one of glycine and hydrogen peroxide existing sludge, process - First International Chemical-Mechanical Polish (CMP) for VLSI / LSI Multilevel Interconnection Conference (CMP-MIC) / First International Conference on Chemical-mechanical Polishing or VLSI / LSI multi-level wiring (CMP-MIC), Santa Barbara, 22.-23. February (1996), and Japanese Patent Application No. 8 (1996) 83780 is a mixture of glycine, hydrogen peroxide and silica with or without benzotriazole for the chemical-mechanical polishing process of Cu with a low Corrosion rate and error rate revealed. In the references will discloses that chemical-mechanical polishing slurry containing a chemical agent such as benzotriazole and n-benzoyl-n-phenylhydroxylamine to form a protective film on copper. The removal rate varies dependent on from the concentration of sludge components. It was about one optimized rate of 120 nm / min. reported with a TiN rate of 30 nm / min. and plate-shaped Wells of 200 nm over the 15 μm wide Structures.

In WO 97/43087 discloses a chemical-mechanical polishing slurry, the one watery Medium, an abrasive, an oxidizer and an organic Acid includes.

In EP-A-0 811 666 discloses a chemical-mechanical polishing slurry, having a pH in the range of 1.5 to 3.0, the Oxidizing agents such as iron (III) nitrate, a fluoride-containing Additive such as hydrofluoric acid in an amount of 0.01 to 0.3% by weight, and having an abrasive, which consists of fine metal particles such as smoked Alumina exists.

at the use of polishing substrates using slurries that Passivating agents such as benzotriazole (BTA), It was discovered that the reaction of benzotriazole with the copper surface during the Polishing a surface film generated, opposite the mechanical action of the abrasive is very resistant, whereby the removal of the surface film is difficult. Furthermore, the degree of passivation is time-dependent and not easy to control what the automation of substrate polishing processes difficult. additionally goes through Benzotriazole an oxidative degradation. Thus, a benzotriazole-containing Mud a short shelf life which limits the manufacturing usability. These properties passivating agents such as benzotriazole complicate the use of machines for polishing passivated substrates in a reproducible manner.

Even though the use of a film-forming mechanism in a chemical-mechanical Polishing process desirable is, remain problems with the formulation of chemical-mechanical slurries consisting of the thickness of the layer of the formed film as well as control problems, making sure that the formed film is abradable is. These problems can film-forming chemical-mechanical polishing slurry have the result unacceptably low polishing rates or poor polishing results to show the day. Thus, the need remains for a chemical mechanical Polishing sludge, which leads to the formation of an ablatable thin passivation layer on a substrate surface and more precisely on the surface a copper alloy-containing substrate is capable of. A desirable one chemical-mechanical polishing slurry will provide good thin-film polishing selectivity to the Lay down and at the same time well polished substrates with minimal dished Create undulations and low error rates.

SUMMARY OF THE INVENTION

The The present invention relates to a chemical mechanical polishing slurry, for polishing metal-containing substrates with repeatable and acceptable rates.

Additional wise the chemical-mechanical polishing slurry has a low insulator polishing selectivity while it high polishing selectivities across from Copper and copper alloy-containing metal layers.

Farther This invention relates to methods of using a single chemical-mechanical polishing slurry for polishing metal layers and in particular copper or copper alloy-containing layers in an integrated circuit.

at an embodiment of this invention, the chemical mechanical polishing slurry comprises an abrasive, at least one oxidizing agent consisting of urea-hydrogen peroxide, Urea peroxide, hydrogen peroxide existing group and mixtures same selected is, and a complexing agent made up of the group of compounds selected is that made of tartaric acid, Salts thereof, and mixtures thereof. The mud contains no Film forming agents.

at a further embodiment this invention is a chemical-mechanical polishing slurry. Of the Mud has an abrasive, an oxidizer, which is made from the group consisting of hydrogen peroxide, urea-hydrogen peroxide and mixtures thereof is, and tartaric acid on. The chemical mechanical polishing slurry has a pH from 5.0 to 9.0, but the slurry is not a film-forming agent contains.

at a further embodiment the invention is a method for polishing a substrate with at least a metal layer. The polishing is done by mixing 1.0 to 15.0% by weight of an abrasive, from 0.3 to 17.0% by weight an oxidizing agent, from 0.1 to 5.0% by weight of at least one complexing agent executed the complexing agent consisting of tartaric acid, salts thereof Group and mixtures thereof is selected, and deionized Water to give a chemical mechanical polishing slurry. The sludge is not mixed with a film-forming agent. The pH the sludge is adjusted to a range of 5 to 9. Then the chemical-mechanical polishing slurry is applied to the substrate, and at least a portion of the metal layer is penetrated by the substrate Contacting a pad with the substrate and moving the pad Pillow in proportion removed to the substrate.

at a further embodiment the invention is a multiple package system for use in manufacture a chemical-mechanical polishing slurry. The multi-package system comprises a first container, having a complexing agent selected from the group of compounds selected is that made of tartaric acid, Salts thereof, and mixtures thereof, and a second Container, having an oxidizing agent consisting of urea-hydrogen peroxide, Urea peroxide, hydrogen peroxide existing group and mixtures same selected is. It is an abrasive positioned in a container made of the one from the first container, the second container or a third container existing group selected is. The multi-package system has no film-forming agent.

DESCRIPTION THE CURRENT EMBODIMENT

The The present invention relates to a chemical mechanical polishing composition precursor and a chemical-mechanical polishing slurry, which itself without a Film forming agent is effective. The chemical-mechanical polishing slurry has an abrasive and the precursor. The precursor includes at least one oxidizing agent and a complexing agent, wherein the oxidizing agent and the complexing agent are selected and formulated in such quantities that the dissolution of the surface of the is inhibited polished substrate. The chemical-mechanical polishing slurry is for use for polishing metals, in particular copper and copper-containing metal layers in conjunction with a substrate suitable, consisting of the integrated circuits, thin films, Multi-level semiconductors and microplates existing group selected is.

In front the description of the details of the various preferred embodiments of this invention will become some terms used in this document Are defined. The chemical mechanical polishing slurry ("CMP slurry") is a usable one Product of this invention containing an oxidizing agent, an abrasive, a complexing agent and other optional ingredients. However, the chemical mechanical polishing slurry does not include a film-forming agent. The chemical mechanical polishing slurry is for polishing multi-level metallizations usable, the semiconductor thin films, thin films integrated circuits, but not limited thereto are, and for any other films, surfaces and substrates in which chemical-mechanical polishing processes are applicable. The terms "copper" and "copper-containing Alloys " used in this document alternately, as it is within the understanding from professionals in this field lies that the terms substrates with layers of pure copper, copper-aluminum alloys and Ti / TiN / Cu and Ta / TaN / Cu multilayer substrates include, but are not limited to.

Of the Chemical mechanical polishing slurry of this invention contains at least an oxidizing agent. The oxidizing agent helps with the oxidation the substrate metal layer or layers into its corresponding oxide, Hydroxide or ions. For example, the oxidizing agent in of the present invention are used to form a metal layer in their corresponding oxide or hydroxide, for example titanium in Titanium oxide, tungsten in tungsten oxide, copper in copper oxide, tantalum in tantalum oxide and aluminum in alumina. The oxidizing agent is suitable when used in a chemical-mechanical polishing slurry for Polishing metals and metal-based components including Titanium, titanium nitride, tantalum, tantalum nitride, copper, tungsten, aluminum and aluminum alloys such as aluminum-copper alloys and various mixtures and combinations thereof is mechanically polished by the metals to the respective Remove oxide layer.

The used in the chemical mechanical polishing slurry of this invention Oxidizing agent is selected from compounds that after reduction Form hydroxyl radicals. Such oxidants provide good polishing selectivities over metal and metal-containing substrate layers, and in particular over copper alloy layers on the day. The oxidizing agent is in particular made from urea-hydrogen peroxide, Urea peroxide and hydrogen peroxide and mixtures thereof selected, where Hydrogen peroxide, urea-hydrogen peroxide and mixtures the same preferred oxidizing agent.

The Oxidant may be present in the chemical mechanical polishing slurry in an amount ranging from about 0.3 to about 30.0% by weight to be available. Preferably, the oxidizing agent is in the chemical-mechanical Polishing slurry of this invention in an amount in the range of about 0.3 to about 17.0 weight%, and most preferably about 1.0 to about 12.0% by weight.

at an embodiment the oxidizing agent is urea-hydrogen peroxide. Because urea hydrogen peroxide consists of 34.5% by weight of hydrogen peroxide and 65.5% by weight of urea, needs a larger amount of weight at urea-hydrogen peroxide contained in chemical mechanical polishing slurry of this invention be to achieve the above-described charge of oxidizing agent. For example, an amount in the range of 1.0 to 12.0 Weight% oxidizing agent is a urea hydrogen peroxide weight, which is three times bigger or 3.0 to 36.0% by weight.

One Urea-hydrogen peroxide-containing chemical-mechanical Polishing sludge can be formulated in a number of methods, including the combination of urea peroxide with water and by combination of urea and hydrogen peroxide in an aqueous solution in a molecular ratio range from about 0.75: 1 to about 2: 1 to a urea-hydrogen peroxide oxidizer to obtain.

Of the chemical-mechanical polishing slurry of this invention differs differs from other chemo-mechanical polishing slurries and in particular from the Polishing of copper layers usable chemical-mechanical polishing sludge thereby, that he in addition to the oxidizing agent does not contain a separate film-forming agent. Examples of such separate film-forming agents used in the compositions of this invention include cyclic compounds such as imidazole, benzotriazole, benzimidazole and benzothiazole. A separate film-forming agent is from the precursor and the sludge compositions omitted this invention to avoid difficulties that in controlling the depth of, and in the subsequent ablation the corrosion-inhibiting agent formed by separate film-forming agents Layers occur.

During the chemical-mechanical polishing is important to the resolution of Substrate surface layer to inhibit surface defects to minimize. One as in conjunction with oxidants as useful The class of compounds found are complexing agents. The chemical-mechanical Sludge of this invention has one of tartaric acid and salts thereof, such as for example, ammonium tartrate, as well as mixtures of the same selected complexing agents on, with tartaric acid most advantageous.

The Complexing agents serve to form a complex with the oxidized Metal, not the underlying unoxidized metal, whereby the depth of the oxidation layer is limited. The complexing agent is in the chemical mechanical polishing slurry of this invention in an amount ranging from about 0.5 to about 5.0% by weight, and preferably in an amount ranging from about 0.5 to about 3.0% by weight present.

It is desirable to maintain the pH of the chemical mechanical polishing slurry of this invention within a range of from about 2.0 to about 12.0, and preferably from about 5.0 to about 9.0, and at most preferably from about 6.5 to about 7.5 to facilitate control of the chemical mechanical polishing process. Slurry processing problems as well as quality problems in polishing the substrate occur when the pH of the CMP slurry of this invention is too low, for example below 2. However, if tartaric acid is selected as the chelating agent, the CMP slurry will produce a pH Value of 2.0, so that an adjustment of the pH to a higher level is necessary.

Of the pH of the chemical mechanical polishing slurry of this invention may be as shown in FIG Use of any known acid, alkali or amine be adjusted. The use of acids or bases that no Metal ions, such as ammonium hydroxide and amines, or nitric, phosphoric, sulfuric or organic acids however, preferred to initiate unwanted metal components in to avoid the chemical mechanical polishing slurry of this invention.

Around the stabilization of a chemical-mechanical polishing slurry this Invention against settling, flocculation and decomposition can promote a variety of optional additions to chemical-mechanical polishing sludge such as surface-active Substances, stabilizers or dispersants are used. If the first chemically mechanical polishing slurry is a surface-active Substance is mixed, it may be an anionic, cationic, nonionic or amphoteric surfactants Act substance, or it can be a combination of two or more surfactants be used. About that In addition, it was found that the admixture of a surfactant Stoffes in reducing the "within-wafer-non-uniformity (WIWNU / die Internal unevenness) the microplates useful can be, reducing the surface of the microplate is improved and microplate flaws be avoided.

In general, the amount of such optional additives as, for example, a surfactant that may be used in the present invention should be sufficient to achieve effective sludge stabilization, typically depending on the particular surfactant selected and the type of surfactant the surface of the metal oxide abrasive will vary. For example, if a selected surfactant is used in an insufficient amount, it will have little or no effect on the stabilization of the chemical mechanical polishing slurry. On the other hand, too much surfactant in the chemical mechanical polishing slurry can result in undesirable foaming and / or flocculation in the slurry. Thus, stabilizers such as surfactants should generally be present in the slurry of this invention in an amount ranging from about 0.001% to about 0.2% by weight, and preferably from about 0.001 to about 0.1% by weight , In addition, the additive may be incorporated directly into the slurry or incorporated on the surface of the metal oxide abrasive using known techniques. In both cases, the amount of additive is adjusted to achieve the desired concentration in the CMP slurry. Preferred surfactants include dodecyl sulfate sodium salt, sodium lauryl sulfate, dodecyl sulfate ammonium salt, and mixtures thereof. Examples of useful surfactants include TRITON ^® DF-16 manufactured by Union Carbide, and SURFYNOL ^® manufactured by Air Products and Chemicals.

Of the Chemical mechanical polishing slurry of this invention comprises an abrasive on. The abrasive is typically a metal oxide abrasive. The metal oxide abrasive can be made of aluminum, titanium earth, Zirconia, germanium, silica, cerium (IV) oxide group and mixtures thereof. The chemical-mechanical Polishing slurry of this invention preferably has about 1.0 to about 15.0% by weight or more of an abrasive. Even more advantageous However, it is when the chemical-mechanical polishing slurry this Invention contains about 2.0 to about 6.0% by weight of abrasive.

The metal oxide abrasive can be made by any technique known to those skilled in the art. Metal oxide abrasives can be made using any high temperature process, such as sol-gel, hydrothermal, or plasma processes, or by processes for producing smoked or precipitated metal oxides. Preferably, the metal oxide is a smoked or deposited abrasive, and more preferably, it is a smoked abrasive such as smoked silica or smoked alumina. The production of smoked metal oxides, for example, is a well-known process which involves the hydrolysis of suitable feedstock vapor (such as aluminum chloride for an alumina abrasive) in a flame of hydrogen and oxygen. Molten, roughly spherical particles whose diameters change as a result of the process parameters are formed during the combustion process. The The molten balls of alumina or similar oxide, which are typically referred to as primary particles, fuse together by undergoing collisions at their points of contact to form branched, three-dimensional chain-like aggregates. The force required to break up aggregates is considerable, and is often considered irreversible. During cooling and collection, the aggregates undergo further collisions, which may result in some mechanical entanglements, thereby forming agglomerates. Agglomerates are believed to be loosely held together by van der Waals forces, and can be reversed, ie, separated, by appropriate dispersion in a suitable medium.

Dejected Abrasives can with conventional Techniques such as coagulation of the desired Particles of an aqueous Medium under the influence of high salt concentrations, acids or other coagulants are produced. The particles become filtered, washed, dried and residues of other reaction products by conventional Separate techniques known to those skilled in the art.

A preferred metal oxide has a surface as prepared by the method of S. Brunauer, PH Emmet and I. Teller, J. Am. Chemical Society, Vol. 60, p. 309 (1938), commonly referred to as BET, ranging from about 5 m ² / g to about 430 m ² / g, and preferably from about 30 m ² / g to about 170 m ² / g. Due to stringent purity requirements of the semiconductor industry, the preferred metal oxides should be those of high purity. High purity means that the total contaminant level of sources such as raw material contaminants and processing trace impurities is typically less than 1%, and preferably less than 0.01% (ie, 100 ppm).

The metal oxide abrasives useful in the slurry of this invention may be metal oxide aggregates or individual spherical particles consist. The term "particle" as used in this Document used refers to aggregates of more than a primary particle and on individual particles.

The Metal oxide abrasive is preferably metal oxide particles with a size distribution of less than about 1.0 micron (i.e., all particles have less as 1.0 micron diameter), an average particle diameter less than about 0.4 microns and with sufficient force around the van der Waals forces to fend off and overcome between abrasive aggregates themselves. It was found that such a metal oxide abrasive effective in minimizing or avoiding scratches, hollows, detached Particles and others while is the grinding resulting surface defects. The particle size distribution in the present invention, using known techniques as determined for example by transmission electron microscopy (TEM) become. The average aggregate diameter refers to the average equivalent spherical diameter using the TEM image analysis, d. H. based on the cross-sectional area of the aggregate. By force is meant that either the surface potential or the hydration force the metal oxide particles must be sufficient to accommodate the van der Waals attractions to repel and overcome the particles.

In another preferred embodiment, the metal oxide abrasive may consist of discrete, single metal oxide particles having a primary particle diameter of less than 0.4 microns (400 nm) and a surface area in the range of about 10 m ² / g to about 250 m ² / g.

Preferably, the metal oxide abrasive is incorporated as a concentrated aqueous dispersion of metal oxides in the aqueous medium of the polishing slurry having from about 3% to about 45% solids, and preferably between 10% and 20% solids. The aqueous dispersion of metal oxides may be prepared using conventional techniques, such as slowly admixing the metal oxide abrasive to a suitable medium, for example deionized water, to form a colloidal dispersion. The dispersion is typically completed by subjecting it to art-known shear mixing conditions in this field. The pH of the dispersion can be adjusted from the isoelectric point to a pH of about 4.0 to maximize colloidal stability. The dispersion is typically diluted with deionized water and other sludge ingredients during the manufacture of the chemical mechanical polishing slurry. The most preferred metal oxide abrasive. is manufactured by Cabot Corporation SEMI-SPERSE ^® W-A355 fumed alumina dispersion. W-A355 is a 9% by weight smoked aluminum dispersion which has a pH of about 4.0.

Although the CMP slurry of this invention can be used to polish any type of metal layer, it has been found that the CMP slurry of this invention has high copper, titanium, titanium nitride, and tantalum nitrate and acceptable tantalum polish rates has. In addition, the CMP slurry exhibits desirable low polishing rates with respect to the dielectric insulating layer.

Of the Chemical-mechanical polishing slurry of this invention may be used manufactured by experts in this field of known conventional techniques become. Typically, the oxidizer and other non-abrasive Medium with predetermined concentrations under low shear conditions in a watery Medium, such as deionized or distilled water mixed until these components are completely dissolved in the medium. A concentrated dispersion of metal oxide abrasive, such as for example smoked Alumina is added to the medium and to the desired level of abrasive input in the final chemical mechanical polishing slurry diluted.

The chemical-mechanical polishing slurry of the present invention as a package system (oxidizer, abrasive and chelating agent in a stable aqueous Medium). To a possible degradation of the chemical-mechanical At least the use of a two-pack system will avoid mudding preferred, wherein the first package the complexing agent, abrasive dispersion and optional additives, and the second package comprises an oxidizer. Other combinations the components of the chemical-mechanical polishing slurry this Invention with two containers are within the knowledge of professionals in this field.

Chemical mechanical polishing slurries of this invention by the combination of one or more complexing agents with one or more metal oxide abrasives and deionized water are formulated, an oxidizer-free chemical-mechanical polishing precursor to surrender. The formulation of chemical-mechanical polishing slurries this Invention of a sludge precursor eliminated with hydrogen peroxide-containing whitewash related stability, transportation and security issues. This is the case because the oxidant-free chemical-mechanical Polishing precursor can also be manufactured and shipped at the place where it is used, and then using an oxidizing agent such as hydrogen peroxide can be mixed to one to give chemical-mechanical polishing slurry.

A optional sludge precursor of this invention comprises an aqueous mixture from urea, at least one complexing agent derived from tartaric acid, salts and mixtures thereof, and at least one Metal oxide. additional Components except a film-forming agent integrated into the urea-containing sludge precursor.

The The most preferred sludge precursor of this invention comprises one smoked Alumina, a complexing agent that is tartaric acid, and a surfactant Substance in the above disclosed amounts of aqueous dispersion. The sludge precursor or mixtures thereof are preferably a pH of about 5.0 to about 9.0.

It can a multi-pack chemical-mechanical polish system along with each any standard polishing equipment used for use on the desired metal layer of the wafer suitable is. The multiple-package system has one or more chemical-mechanical Polishing slurry components as appropriate in aqueous or dry form in two or more containers on. The multi-pack system is made possible by the combination of components from the different containers in the desired Quantities used on a substrate to form a chemical-mechanical polishing slurry to give at least one oxidizing agent, a complexing agent and at least one abrasive in the above-mentioned amounts, what before or at the time of applying the slurry to a substrate he follows. The preferred package system includes a first container that contains a precursor of a chemical-mechanical polishing slurry, the Alumina, urea, a complexing agent, the Tartaric acid, Ammonium tartrate and mixtures thereof is selected, a surface-active Fabric having a pH of about 5.0 to about 8.0, and a second Container, having the hydrogen peroxide. At the polishing site will be a previously selected Amount of the precursor of a chemical-mechanical polishing slurry and a selected one Amount of hydrogen peroxide combined at the time of polishing, to a chemical mechanical polishing slurry of this invention result.

The chemical mechanical polishing slurry of the present invention does not greatly increase the silica polishing rate. The chemical mechanical polishing slurry of this invention, however, polishes copper, titanium, titanium nitride, tantalum and tantalum nitride layers at good rates under controllable conditions. Thus, the chemical mechanical polishing slurry of the present invention is in the control of polishing selectivities of titanium, copper, titanium nitride, tantalum and tantalum nitride layers. The polishing slurry of the present invention may be used during the various stages of semiconductor integrated circuit fabrication to provide effective polishing at desired polishing rates while minimizing surface imperfections and defects.

EXAMPLES

We have discovered that a film-forming agent-free chemical-mechanical Polishing sludge comprising at least one oxidizing agent and a complexing agent specific types and amounts for polishing multiple metal layers and thin films at high rates, the copper alloys, titanium and titanium nitride, Tantalum and tantalum nitride, while having a good selectivity to dielectric layers puts on the day.

The The following examples illustrate preferred embodiments This invention and preferred methods of using compositions this invention.

EXAMPLE I

at this example becomes the resolution and corrosion of copper in the presence of chemical-mechanical slurries evaluated with and without the film-forming agent benzotriazole. The rate the Cu dissolution while of the chemical mechanical polishing process is ex situ (i.e., not on the polishing table) using a rotating Cu disk electrode (with a Pine rotator) and a 273 potentiostat with corrosion Software (from EG & G, PAR). A platinum mesh electrode serves as an additional electrode, and a saturated one Mercury sulfate electrode (MSE) is used as a reference electrode. Electrochemical data were at a preselected electrode speed of 500 rpm (or a maximum of 19.94 m / sec.), the rotator and the electrode in contact with a sanding pad (with a downward force of 1.2 kg or 5.9 psi), or over the Pillows were raised.

The Device can be the metal dissolution measure while the metal surface is sanded (or polished on the polishing tool), or after sanding. The abrasion value is considered to that he is an approximation of the chemical Rate during of polishing is while the measurements after grinding the corrosion rate of the metal in a given mud. Typically, the electrochemical Data recorded as potentiodynamic polarization curves, where the potential of about -0.25 V cathodic to the open circuit potential to an anodic potential at a rate of 10 mV / sec. is driven.

Each of the evaluated sludges had a pH of 7.0. The used alumina in the sludge, there was a SEMI-SPERSE ^® W-A355- dispersion of fumed alumina, which was manufactured by Cabot Corporation and diluted to the desired loading level. The copper dissolution rate measured with the device as a current density was referred to Å / min. recalculated and is listed for several slurries in Table I.

Table I

The results show that the rate of Cu dissolution during and after the abrasion is relatively low using sludges containing only H ₂ O ₂ (and a surfactant) when the Cu surface is covered with Cu oxide (sludge 2 ) is passivated. Additions of benzotriazole to H ₂ O _{2 result} in an additional surface film with a Cu dissolution rate with and without abrasion in single digits (sludge 1). After admixing a strong chelating agent such as ammonium oxalate to the slurries, the Cu dissolution rate with abrasion is 100 times higher (see sludge 2 and 4) than peroxide alone, while the Cu corrosion rate is from about 5 to 60 Å / min. elevated. The use of a film-forming agent such as benzotriazole reduces the Cu dissolution rate to 96 Å / min. with abrasion and 1.4 Å / min. after the abrasion. With tartaric acid, slurries 5 and 6, the dissolution rate of Cu with or without attrition, with or without benzotriazole, is still relatively low. Thus, the passivation ability of the oxidizing agent with this complexing agent is not significantly affected, and the film-forming agent benzotriazole is not needed to limit the Cu corrosion rate.

EXAMPLE II

This example evaluates the ability of chemical mechanical polishing slurries with and without 0.04 weight percent benzotriazole filming agent to polish various substrate layers. Each slurry included 2.0 wt% H ₂ O _2, 1.0 wt% tartaric acid, 3.0% by weight of Cabot Corporation prepared SEMI-SPERSE ^® W-A355 fumed alumina dispersion, and 50 ppm Triton DF-sixteenth The pH of each slurry was adjusted to 7.0 prior to use using NH ₄ OH.

Each CMP slurry was coated onto PVD copper microplates having a Ti, TiN or TA underlayer on an IPEC 472 polisher, and using an IC1000 / SUBA IV pad stack manufactured by Rodel, Inc. with a downward force of 3 psi (20.7 x 10 ³ Pa), a table speed of 55 rpm. and a spindle speed of 30 rpm. and a back pressure of 0.8 psi (5.49 x 10 ³ Pa). The polishing data is listed in Table II below.

Table II

The Results show that the polishing performance in the muds with and without benzotriazole, and in the sludge without Benzotriazole slightly improved when dish-shaped depression and erosion considered become.

EXAMPLE III

The removal rates of Cu, Ta and glass were determined in this example using slurries with different concentrations of H ₂ O ₂ and tartaric acid at a pH of 7.0. In the slurry used in each abrasive it was manufactured by Cabot Corporation SEMI-SPERSE ^® W-A355 fumed alumina dispersion. The polishing results are listed in Table 3. PVD copper microplates were molded using a IPEC 472 tool with a downward force of 3 psi (20.7 x 10 ³ Pa), a back pressure of 0.6 psi (4.13 x 10 ³ Pa), a table speed of 55 rpm. and a carrier speed of 30 rpm. polished.

Table III

The Results shown in Table III show that the higher the weight ratio of peroxide to tartaric acid The smaller the Cu removal rate (i.e., the better the Passivation).

The The present invention is a chemical mechanical polishing slurry precursor and sludge produced therefrom which contains no film-forming agent, and instead an abrasive, at least one oxidant and comprises at least one complexing agent. Chemical-mechanical polishing slurry of this Invention are for polishing metal layers in a controllable manner and way able by making a reproducibly thin passivation layer form.

When Result will be less variability initiated in the process, the polishing performance of the sludge is more consistent and controllable, the polishing results are good, and the storage time will be raised.

The The present invention has been accomplished by way of specific embodiments described. The scope of the invention is intended to be that in the specification The description and examples set forth are not intended to be limited rather, as defined by the following claims.

Claims (34)

Chemical-mechanical polishing slurry, the following having: An abrasive; at least one oxidizing agent, which consists of urea hydrogen peroxide, urea peroxide, Hydrogen peroxide and mixtures thereof is selected; and about 0.1 to 5.0% by weight of a complexing agent, the selected from the group of compounds consisting of tartaric acid, salts and mixtures thereof, and wherein the sludge contains no film-forming agent. Chemical-mechanical polishing slurry according to claim 1, characterized in that the complexing agent is tartaric acid. Chemical-mechanical polishing slurry according to claim 2, characterized in that the tartaric acid in an amount in the range from 0.5 to 3.0% by weight is present. Chemical-mechanical polishing slurry according to claim 1, characterized in that the oxidizing agent is a compound is that forms after the reduction of hydroxyl radicals. Chemical-mechanical polishing slurry according to claim 1, characterized in that the hydrogen peroxide in a Amount in the range of 0.3 to 17% by weight is present. Chemical-mechanical polishing slurry according to claim 1, characterized in that the sludge has a pH of 5 to 9. Chemical-mechanical polishing slurry, the following having: An abrasive; an oxidizing agent which from the hydrogen peroxide, urea hydrogen peroxide and Mixtures thereof is selected from the group; and Tartaric acid, where the chemical-mechanical polishing slurry has a pH of 5 to 9 and wherein the slurry does not contain a film-forming agent. Chemical-mechanical polishing slurry according to claim 7, characterized in that the oxidizing agent is hydrogen peroxide is. Chemical-mechanical polishing slurry according to claim 7, characterized in that the oxidizing agent is urea-hydrogen peroxide is. Chemical-mechanical polishing slurry according to claim 7, characterized in that the tartaric acid in the mud in a Amount in the range of 0.5 to 3.0% by weight is present. Chemical-mechanical polishing slurry according to claim 7, characterized in that the abrasive means at least one Metal oxide is. Chemical-mechanical polishing slurry according to claim 11, characterized in that the metal oxide abrasive the alumina, cerium (IV) oxide, germanium, silica, titania, zirconia and mixtures thereof is selected. Chemical-mechanical polishing slurry according to claim 7, characterized in that the abrasive is an aqueous dispersion of a metal oxide. Chemical-mechanical polishing slurry according to claim 11, characterized in that the metal oxide abrasive Metal oxide aggregates consisting of a size distribution of less than 1.0 micron and an average aggregate diameter of less than 0.4 microns. A chemical mechanical polishing slurry according to claim 11, characterized in that the metal oxide abrasive consists of discrete single metal oxide spheres having a primary particle diameter of less than 0.4 microns and a surface area in the range of 10 m ² / g to 250 m ² / g. Chemical-mechanical polishing slurry according to claim 7, characterized in that the abrasive has a surface area in the range of 5 m ² / g to 430 m ² / g. Chemical-mechanical polishing slurry according to claim 7, characterized in that the abrasive has a surface area of 30 m ² / g to 170 m ² / g. Chemical-mechanical polishing slurry according to claim 7, characterized in that the abrasive is deposited from the Abrasives or smoked Abrasives existing group is selected. Chemical-mechanical polishing slurry, the following having: 1.0 to 15.0% by weight of an aluminum abrasive; 1.0 to 12.0% by weight of hydrogen peroxide; and 0.5 to 3.0% by weight Tartaric acid, the composition being adjusted to a pH of 5 to 9 and wherein the slurry does not contain a film-forming agent. Chemical-mechanical polishing slurry according to claim 19, characterized in that it has at least one surface-active Has fabric. A method of polishing a substrate having at least one metal layer comprising the following Steps comprises: (a) admixing from 1.0 to 15.0% by weight of an abrasive, from 0.3 to 17.0% by weight of an oxidizing agent consisting of the urea-hydrogen peroxide, urea peroxide, hydrogen peroxide and mixtures thereof Group is selected, 0.1 to 5.0% by weight of at least one complexing agent, wherein the complexing agent is selected from tartaric acid, salts thereof and mixtures thereof, and deionized water to give a chemical mechanical polishing slurry, wherein the sludge contains no film-forming agent; (b) adjusting the pH of the slurry to a range of 5 to 9; (c) applying the chemical-mechanical slurry to the substrate; and (d) removing at least a portion of the metal layer from the substrate by contacting a pad with the substrate and moving the pad relative to the substrate. Method according to claim 21, characterized that the substrate comprises a copper alloy-containing layer. Method according to claim 21, characterized that the substrate further comprises a titanium and titanium nitride layer, wherein at least a portion of the titanium and titanium nitride layers in step (c) is removed. Method according to claim 21, characterized that the chemical-mechanical polishing slurry is applied to the pad is before the pad is brought into contact with the substrate. Method according to claim 21, characterized that the oxidizing agent is hydrogen peroxide, urea-hydrogen peroxide and mixtures thereof. Method according to claim 21, characterized that the complexing agent is tartaric acid is. Method according to claim 21, characterized that the chemical-mechanical polishing slurry has a pH of 5.0 to 9.0. Method according to claim 21, characterized that the abrasive is a metal oxide. Method according to Claim 28, characterized that the metal oxide abrasive consists of the aluminum oxide, cerium oxide, Germanium, silica, titania, zirconia comprehensive group and mixtures thereof is. Method according to claim 21, characterized that the abrasive is an aqueous Dispersion of a metal oxide. Method according to claim 30, characterized in that that the metal oxide abrasive is precipitated from the Alumina, smoked Alumina, precipitated silica and mixtures thereof existing group selected is. Method for polishing a substrate with a copper-containing alloy layer, a titanium layer and a titanium nitride layer, which comprises: (a) admixing from 1.0 to 15.0 Weight percent of alumina, from 1.0 to 12.0 weight percent hydrogen peroxide, from 0.5 to 3.0% by weight of tartaric acid and deionized water to a chemical mechanical polishing slurry giving the copper alloy titanium polishing selectivity [Cu: Ti] less than about 4. (B) Adjusting the pH of the chemical mechanical polishing slurry to 5.0 to 9.0; (c) applying the chemical mechanical polishing slurry on the substrate; and (d) removal of at least part of the Copper alloy layer and at least a portion of the titanium nitride layer by contacting a pad with the substrate and agitating of the pillow in proportion to the substrate. A multi-package system for use in making a chemical mechanical polishing slurry, comprising: (a) a first container having a complexing agent selected from the group of compounds consisting of tartaric acid, salts thereof, and mixtures thereof, (b) a second container having an oxidizing agent selected from urea hydrogen peroxide xid, urea peroxide, hydrogen peroxide and mixtures thereof; and (c) an abrasive agent positioned in a container selected from the group consisting of the first container, the second container or a third container, characterized in that the multi-package system has no film-forming agent. Chemical-mechanical polishing slurry according to claim 1, which has An abrasive; an oxidizing agent, which is made from urea hydrogen peroxide, Urea peroxide and mixtures thereof is selected; about 0.1 to 5.0% by weight of a complexing agent selected from the group of compounds selected is that made of tartaric acid, Salts thereof and mixtures thereof, and where the Mud contains no film-forming agent.